This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A189036 #7 Mar 31 2012 10:28:21 %S A189036 0,2,3,1,5,30,7,6,6,70,11,12,13,126,120,2,17,42,19,30,210,286,23,66, %T A189036 10,390,1,56,29,930,31,10,462,646,420,15,37,798,624,170,41,1722,43, %U A189036 132,195,1150,47,21,14,90,1020,182,53,6,880,322,1254,1798,59,345,61,2046,357,3,1170,4026,67,306,1794,4130,71,78,73,2886,165,380,1386,5538,79,55,12,3526,83,651,1870,3870,2784,770,89,1230,1820,552,3162,4606,2280,102,97,154,825,35 %N A189036 a(n)= lcm(n,n')/gcd(n,n'), where n' is the arithmetic derivative of n. %C A189036 Least common multiple of n and its arithmetic derivative divided by greatest common divisor of n and its arithmetic derivative. %F A189036 a(n) = lcm(n,n')/gcd(n,n') = A086130(n)/A085731(n). %e A189036 n = 8, n'= 12, lcm(8,12)= 24, gcd(8,12)= 4, hence a(8)=24/4 = 6. %Y A189036 Cf. A003415, A085731, A086130, A083345, A083346. %K A189036 nonn %O A189036 1,2 %A A189036 _Giorgio Balzarotti_, Apr 15 2011